SLC8000: Improper Limitation of a Pathname to a Restricted Directory
CVE-2026-80155 is a critical-severity improper limitation of a pathname to a restricted directory vulnerability in SLC8000 from Lantronix, with a CVSS 3.1 base score of 10.0 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 9.7.0.5 as the first without the flaw, so updating SLC8000 to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 1.03% chance of exploitation within 30 days, higher than 64% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update SLC8000 to 9.7.0.5 or a later version.
- Update EMG8500 to 9.7.0.1 or a later version.
- Update EMG7500 to 9.7.0.1 or a later version.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| LANTRONIX | SLC8000 | before 9.7.0.5 | 9.7.0.5 |
| LANTRONIX | EMG8500 | before 9.7.0.1 | 9.7.0.1 |
| LANTRONIX | EMG7500 | before 9.7.0.1 | 9.7.0.1 |
| LANTRONIX | SLB882 | Not specified in the record | Not stated |
| LANTRONIX | SLCx-03 | Not specified in the record | Not stated |
| LANTRONIX | SLCx-02 | Not specified in the record | Not stated |
| LANTRONIX | SLC9000 | before 9.7.0.2 | 9.7.0.2 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H. Scored by CNA (vulncheck.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 10.0 | Critical | CNA (vulncheck.com) |
| CVSS 3.1 | 10.0 | Critical | CNA (vulncheck.com) |
Official description
Lantronix SLC8000 before firmware v9.7.0.5, SLC9000 before firmware v9.7.0.2, EMG8500/EMG7500 before firmware v9.7.0.1, and all firmware versions of SLB882/SLCx-03/SLCx-02 contain an authentication bypass vulnerability in the web management portal upload endpoint that allows unauthenticated attackers to read sensitive configuration files and upload files to arbitrary filesystem locations, leading to remote code execution. The web configuration server constructs the session cookie file path using snprintf with a fixed-size buffer; by supplying a cookie value of a specific length an attacker causes the path to truncate at the required delimiter and leverages path traversal to redirect authentication validation to an arbitrary on-disk file such as the local user database, bypassing all session checks. Attackers can use this vulnerability to achieve complete loss of confidentiality, integrity, and availability on the affected device and potentially impact downstream serial-connected devices.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Limitation of a Pathname to a Restricted Directory
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
How developers prevent this class of flaw
- For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
- Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth.
More Improper Limitation of a Pathname to a Restricted Directory vulnerabilities (CWE-22)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other references
- revrb.net/2026/09/21/revrb-lantern.html
- ts.lantronix.com/ftp/SLC9000/9.7.0.2R1/
- ts.lantronix.com/ftp/emg/EMG_7500/9.7.0.1R2/
- ts.lantronix.com/ftp/emg/EMG_8500/9.7.0.1R2/
- ts.lantronix.com/ftp/slc8000/9.7.0.5R2/
- vulncheck.com/advisories/lantronix-autonomous-out-of-band-devices-unauthenticated-authentication-bypass-via-s…
Other vulnerabilities in SLC8000
- 9.1 Critical severity
- 9.6 Critical severity
- 9.1 Critical severity
- 9.1 Critical severity
- 7.5 High severity
- 8.6 High severity
Recent Improper Limitation of a Pathname to a Restricted Directory vulnerabilities
- 9.9 Critical severity
- 7.5 High severity
- 8.6 High severity
- 7.7 High severity
- 8.6 High severity
- 7.1 High severity
Spotted an error? Tell us.